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Mutual friction and vortex Hall angle in a strongly interacting Fermi superfluid
N Grani1,2,3,4, D Hernández-Rajkov2,3,4, C Daix1,2,5
1Department of Physics, University of Florence, Sesto Fiorentino, Italy.
Nature Communications
|November 21, 2025
Summary
Researchers measured friction coefficients in unitary Fermi superfluids by tracking vortex motion. These findings reveal insights into quantum turbulence and quasiparticle behavior near the superfluid transition.
Area of Science:
- Condensed Matter Physics
- Quantum Fluids
- Superfluidity
Background:
- Unitary Fermi superfluids exhibit complex vortex dynamics.
- Understanding vortex-antivortex interactions is crucial for superfluid behavior.
- Mutual friction coefficients are key to quantifying inter-component coupling.
Purpose of the Study:
- To investigate the 2D motion of a single vortex around a pinned anti-vortex.
- To measure unknown longitudinal and transverse mutual friction coefficients.
- To explore the relationship between vortex dynamics and superfluid properties.
Main Methods:
- Analysis of vortex trajectories in a unitary Fermi superfluid.
- Measurement of mutual friction coefficients.
- Comparison with numerical simulations and analytic models.
Main Results:
- Measured longitudinal and transverse mutual friction coefficients.
- Observed an increase in coefficients approaching the superfluid transition.
- Determined the vortex Hall angle and vortex Reynolds number (Reα).
Conclusions:
- Vortex dynamics are significantly influenced by thermal excitations and bound quasiparticles.
- The study provides a new platform for investigating vortex dynamics at finite temperatures.
- Results align well with theoretical models and simulations.
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